BBCode [url][/url] tag fails with commas

[Alex Li]

In comments, the following successful produces a hyperlink:
[url]http://wcipeg.com/problems/sort=date[/url]

However, adding a simple comma at the end (i.e. to add more filter parameters), like so:
[url]http://wcipeg.com/problems/sort=date,[/url]
displays the entire raw source with the BBCode tag, without actually creating a link.